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Found in Malaysia, South East Asia. Small insect with wingspan of around 1 centimetre. Its back legs and abdomen are pointed away from the wall.
That is a moth, (Lepidoptera), in the family Pterophoridae. It looks very much like Stenodacma wahlbergi. https://en.wikipedia.org/wiki/Stenodacma_wahlbergi
Diseases and Insect Pests found in Chrysanthemum
A number of diseases and insect pests have been found damaging chrysanthemum. If these are not controlled at right time, these can cause severe damage to the crop.
Important disease is as follows:
Diseases found in Chrysanthemum:
It is caused by Septoria obesa and S. Chrysanthemella and is a serious disease. Greyish brown circular spots appear on the leaves. Leaves turn yellow and die. It can be controlled by spraying 0.2% Zineb or Dithane M-45.
It is caused by a fungus (Oidium chrysanthemi). The disease is characterised by the white powdery mass on leaves and stems. To control this disease spraying with 0.5% Kerathane (40 E.C.) has been found useful.
Flower rot. It is caused by grey mould (Botrytus cirterea) which appears as brown water soaked spots on the petals. The infected flowers show tan or light brown specks at the base of petals which may result complete rotting. It can be controlled by spraying 0.2% Zineb or Dithane M-45.
Insect-Pests found in Chrysanthemum:
Aphids (Myzus persicae):
Black aphids appear at the time of flowering and suck the cell sap of stem, stalk, bud, flowers, etc. Flowering is affected drastically. It can be controlled by applying Thimet in soil or by spraying Rogor 30 EC or Metasystox 25 EC @ 250 ml in 250 L of water.
Red hairy caterpillar (Amasacta moorie):
The larvae eat away the foliage leaving only the skeleton of veins. At later stages larvae migrates to other plants. It can be controlled by spraying 500 ml Thiodan or 200 ml of Nuvan in 200 L of water/acre.
Gram caterpillar (Heliothis armigera):
The caterpillar which are of green, black and yellow colour attack the flower buds and eat them away. Their presence is indicated by very fine holes. It can be controlled as in case of red hairy caterpillar.
Poisonous snakes in Malaysia.
In Malaysia there are more than 40 different species of dangerous front fanged snakes.
18 species are found on the land, and 22 species of snakes can be found in the sea surrounding Malaysia.
Over a period of 22 years, some 55,000 snake bites were recorded in the Malaysian hospitals. This figure does not include the un-reported snake bites.
The mortality rate of all snake bites in Malaysia in less than 5%.
New Species of ‘Exploding Ant’ Discovered: Colobopsis explodens
Entomologists are claiming they have discovered a new species of so-called ‘exploding ant’ living in the remote rainforests of Borneo, Thailand, and Malaysia. When their colony is threatened by an intruder, minor workers of the new species — named Colobopsis explodens — can tear their own body apart, in order to release toxins and either kill or repel the enemy. Colobopsis explodens is described in a paper published online April 19 in the journal ZooKeys. Watch this video to see the behavior of exploding ants in various settings.
Major worker of Colobopsis explodens with characteristically enlarged head. Image credit: Heinz Wiesbauer.
“Amongst the countless fascinating plants and animals inhabiting the tropical rainforests of Southeast Asia, there are the spectacular ‘exploding ants,’ a group of arboreal, canopy dwelling ants nicknamed for their unique defensive behavior,” explained lead author Dr. Alice Laciny of the Natural History Museum Vienna, Austria, and colleagues.
“When threatened by other insects, minor workers can actively rupture their body wall. Apart from leading to the ants’ imminent death, the ‘explosion’ releases a sticky, toxic liquid from their enlarged glands, in order to either kill or hold off the enemy.”
These ants were first recorded exploding in 1916, but no new species had been described since 1935, due to insufficient evidence.
Instead, entomologists used to simply refer to them as the members of the Colobopsis cylindrica group.
That was until Dr. Laciny and co-authors came together led by their shared fascination with these insects and their extraordinary mechanism of self-sacrifice (also called autothysis) in 2014.
Minor worker of Colobopsis explodens with posterior body raised in a defensive pose. Image credit: Alexey Kopchinskiy.
Colobopsis explodens has been picked as the model species of the group, after the researchers deemed it to be ‘particularly prone to self-sacrifice when threatened by enemy arthropods, as well as intruding scientists.’
“While minor workers of Colobopsis explodens exhibit the ability to ‘explode,’ the other castes have specialties of their own,” Dr. Laciny and colleagues said.
“For example, major workers — also called ‘doorkeepers’ — have big, plug-shaped heads used to physically barricade the nest entrances against intruders.”
“During a sampling trip to Brunei in 2015, we even managed to observe queens and males on a mating flight. We sampled the first males of these ants ever to be seen.”
“We also recorded the ants’ activity schedule and conducted the first experiments on food preferences and exploding behavior.”
A. Laciny et al. 2018. Colobopsis explodens sp. n., model species for studies on ‘exploding ants’ (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group. ZooKeys 751: 1-40 doi: 10.3897/zookeys.751.22661
World’s Second-Longest Insect Discovered in Vietnam
Dr Joachim Bresseel holding a 31.7-cm-long female Phryganistria heusii yentuensis. Image credit: Joachim Bresseel / Jerome Constant.
In the jungles of Vietnam, biologists Dr Joachim Bresseel and Dr Jerome Constant from Royal Belgian Institute of Natural Sciences have discovered two new species and one new subspecies of Phasmatodea, an order of insects whose members are known as stick insects.
The latter, named Phryganistria heusii yentuensis, is the second-longest insect known to date.
The current record-holder is another stick-insect called Phobaeticus chani. It is found on the Indonesian island of Borneo and measures a huge 36 cm in length.
Phryganistria tamdaoensis, male. Image credit: Joachim Bresseel / Jerome Constant.
According to the team, Phryganistria heusii yentuensis is “currently recorded from Tay Yen Tu Nature Reserve located in Luc Nam and Son Dong Districts, Bac Giang Province, about 150 km ENE of Hanoi. Another specimen is also reported from northeast Vietnam: Mount Mauson, 30 km E of Lang Son city.”
The other two newfound species are Phobaeticus trui and Phryganistria tamdaoensis.
Stick insects first appeared in the fossil record over 40 million years ago and are related to cockroaches, mantids and, more distantly, the grasshoppers and crickets.
Phobaeticus trui, male. Image credit: Joachim Bresseel / Jerome Constant.
There are around 3,000 known species, mainly living in the tropics and subtropics where some species may be up to 30 cm in length.
They are slow-moving insects, a behavior pattern that is consistent with their cryptic lifestyle. When discovered they will often drop to the ground and remain motionless rather than take flight. Some species will also shed legs when attacked, growing them back over time.
All stick insects are herbivores as both adults and nymphs feeding on the leaves of trees and shrubs.
The description of the new species of stick insects appears in the open-access journal European Journal of Taxonomy.
Joachim Bresseel & Jerome Constant. 2014. Giant Sticks from Vietnam and China, with three new taxa including the second longest insect known to date (Phasmatodea, Phasmatidae, Clitumninae, Pharnaciini). European Journal of Taxonomy 104: 1–38 doi: 10.5852/ejt.2014.104
Diversity and abundance of some insect fauna in Krau Wildlife Reserve Forest, Malaysia
Credit: C.C. tonrulkens http://www.flickr.com/photos/[email protected]/4483279535/
Concerned about habitat changes due to logging and rapid development, Universiti Teknologi MARA researchers recently conducted a study on the diversity of the important Hymenoptera group, which includes bees, wasps and ants. Their results will be useful in forest conservation programmes.
This study was initiated due to the changes taking place to the natural habitat of insects due to logging and development. These activities pose a great threat to insect communities in the forest.
The study focused on Hymenoptera known as the most important group of insects in any terrestrial ecosystem. Bees, wasps and ants are some of the insects in this group. They are important pollinators of flowering plants as well as predators of many arthropods. As such, many of them can be classified as the key stone species in a particular ecosystem.
Preliminary observation showed that the Hymenopteran were quite diverse at the Krau Wildlife and Forest Reserve (KWFR), Pahang, geographically considered as a lowland dipterocarp forest, which is connected to the Malaysian National Park. The objective of this study was to determine the level of biodiversity, abundance and richness of Hymenoptera in Kuala Lompat, Krau Wildlife Forest Reserve and to study its relationship, if any, between changes in environmental gradient from forest fringes and deeper into the forest.
The findings of this study indicated that certain species of insects were found in abundance along the fringes of the forest where many species of flowering plants were found. However, closed and narrow areas deeper in the forest with many trees, shrubs and grass provided shelter for the insects from predators for example birds and therefore constituted a higher diversity of Hemiptera compared to those found at the forest fringes or along the river which is more open and exposed to predators.
In conclusion, the study area in KWFR forest, Kuala Lompat recorded 1236 specimens and 55 morphospecies of insects under order Orthoptera, Hemiptera and Diptera. For Orthoptera and Diptera, forest fringes recorded the highest abundance while for Hemiptera, the most abundant individuals were found in the interior of the forest. Orthoptera, Hemiptera and Diptera could be used as a bio indicator in Malaysian forest because their ease in identification process and well known taxonomic. This method is useful and should be used by ecologist in forest conservation program.
Fossils show 66 million years of insects eating kauri trees
Agathis microstachya and Agathis robusta growing near Lake Barrine, Australia. Credit: Cleveland Museum of Natural History
Exquisitely preserved feeding marks on fossil conifer leaves show that the same insect feeding and fungi persisted for millions of years on the same type of plant, from ancient Patagonian rainforests to the modern rainforests of the tropical West Pacific.
Over 50 million years ago, rainforests teeming with life stretched across the ancient supercontinent Gondwana, including what is now South America, Antarctica and Australia. Based on fossil evidence, many plants that now live in places like Australia, New Guinea and Borneo are survivors from the Gondwanan rainforest. Fossil leaves from the Patagonian region of southern Argentina also preserve an astonishing variety of insect-feeding damage traces like those seen in modern rainforests, showing that the Gondwanan forests were also home to diverse plant-feeding insect communities. Did those ancient plant-insect communities survive the breakup of Gondwana and the dramatic range changes of the host plants, and are they still alive today?
An international group of researchers focused on fossils of Agathis, a majestic, tall conifer commonly known as kauri, comparing thousands of modern specimens from Australasia and Southeast Asia to 482 Patagonian fossils ranging in age from 66 to 48 million years, latest Cretaceous to middle Eocene. Their findings were published today (Nov. 25) in Communications Biology.Leaf mine on a leaf of cf. Agathis from the latest Cretaceous Lefipán Formation, Chubut, Argentina. Similar blotch mines on Agathis from before and after the Cretaceous-Paleogene extinction (when the non-avian dinosaurs went extinct) represent the first evidence of a probable surviving leaf mine association on the same plant genus during the mass extinction. Credit: Cleveland Museum of Natural History
"We found remarkably similar suites of insect and fungal damage on fossil and living Agathis leaves over a vast span of time and space," said Dr. Michael Donovan, Senior Collections Manager of Paleobotany & Paleoecology at the Cleveland Museum of Natural History and lead author of the paper.
Insects have evolved many different plant-feeding strategies, and hundreds of damage types have been recognized in the fossil record. On both the fossil and modern Agathis leaves, the team found highly specialized leaf mines that insect larvae create as they tunnel through leaves, tumor-like galls, bite marks along leaf edges from hungry insects, the waxy protective armor of scale insects, and rust fungi.
Notably, the researchers found extremely similar elongated, blotchy leaf mines on Agathis at all the fossil sites and on multiple living species of the same conifer.
"While working on a previous study on the recovery of insect feeding after the end-Cretaceous "dinosaur" extinction, I surveyed over 20,000 Patagonian and North American leaf fossils," said Dr. Donovan. "The leaf mines on Agathis are the only evidence I found for any type of leaf mine on the same host plant surviving the dinosaur extinction."
The separation of South America from Antarctica led to cooling and drying in Patagonia, and over millions of years, the high-diversity rainforest, including Agathis, disappeared from Patagonia, replaced by the grasslands and lower-diversity temperate rainforests of today. Agathis requires consistently rainy conditions to survive and must have tracked rainforest habitats throughout its history as the Earth's plates moved, leading to its current distribution in warm, wet areas from New Zealand to Malaysia.
The researchers said that the environmental tracking by Agathis as the southern continents moved into their current positions might have provided stable conditions that led to the establishment of long-term relationships between Agathis and the insects and fungi that depend on it, even as its range has shifted massively. The scientists said it is also possible that unrelated groups of insects fed upon Agathis in similar ways at different points in its history.
"I've walked in mountain rainforests of Australia and Borneo and seen exactly the same feeding patterns on living kauri trees as in 65-million-year-old fossils that we've collected in Argentina," said Dr. Peter Wilf, professor of geosciences at Penn State University and a participant in the study. "It's absolutely stunning, all the more so because these communities and the threatened biodiversity and evolutionary history they represent were never noticed before, and we're documenting them first from fossils."
Insects & Flowers
The mega-nosed fly (Moegistorhynchus longirostris) of southern Africa, like its literary counterpart, Pinocchio, has a bizarre appearance that reveals an underlying truth. Its proboscis, which looks like a nose but is actually the longest mouthpart of any known fly, protrudes as much as four inches from its head–five times the length of its bee-size body. In flight the ungainly appendage dangles between the insect’s legs and trails far behind its body.
To an airborne fly, an elongated proboscis might seem a severe handicap (imagine walking down the street with a twenty-seven-foot straw dangling from your mouth). Apparently, though, the handicap can be well worth its aerodynamic cost. The outlandish proboscis gives the mega nosed fly access to nectar pools in long, deep flowers that are simply out of reach to insects with shorter mouthparts.
But that poses a conundrum: why would natural selection favor such a deep tube in a flower? After all, nectar itself has evolved because it attracts animals that carry pollen, the sperm of the floral world, from one plant to another. And since pollinators perform such an essential service for the flower, shouldn’t evolution have favored floral geometries that make nectar readily accessible to the pollinators?
Yet the story of the long proboscis of the mega-nosed fly and the long, deep tubes of the flowers on which it feeds is not quite so straightforward. There are subtle advantages, it turns out, to making nectar accessible to only a few pollinators, and nature factors those advantages into the evolutionary equation as well. In fact, the evolution of those two kinds of organisms, pollinator and pollinated, presents an outstanding example of an important evolutionary phenomenon known as coevolution. Coevolution can explain the emergence of bizarre or unusual anatomies when no simple evolutionary response to natural selection is really adequate. It can help conservationists identify species that could be vital in maintaining a given habitat. And it can help naturalists investigating novel plants predict what kinds of animals might pollinate their flowers.
The coevolution of the mega nosed fly and the plants it pollinates is a tale of extreme specialization. Each species has adapted to changes in the other in ways that have left each of them, to some degree, reliant on the other. The idea that a plant species might become dependent for pollination on a single species of animal goes back to the writings of Charles Darwin. For example, Darwin noted, the flower spur of the Malagasy orchid (Angraecum sesquipedale) contains a pool of nectar that is almost a foot inside the opening of the flower. (A flower spur is a hollow, hornlike extension of a flower that holds nectar in its base.) In pondering the evolutionary significance of those unusual flowers, Darwin predicted that the orchid must be adapted to a moth pollinator with a long proboscis.
Critical to Darwin’s prediction was his suspicion that pollination could take place only if the depth of a plant’s flowers matched or exceeded the length of a pollinator’s tongue. Only then would the body of the pollinator be pressed firmly enough against the reproductive parts of the flower to transfer pollen effectively as the pollinator fed. Thus, as ever deeper flowers evolved through enhanced reproductive success, moths with ever longer proboscises would also, preferentially, live long enough to reproduce, because they would most readily reach the available supplies of nourishing nectar. Longer proboscises would lead yet again to selection for deeper flower tubes.
The result would be the reciprocal evolution of flowers and pollinator mouthparts. That coevolutionary process would cease only when the disadvantages of an exaggerated trait balanced or outweighed its benefits. Given enough time, the process might even produce new species: an insect the specializes in feeding on nectar from deep flowers, and a deep-flowered plant specialized for being pollinated by insects with long mouthparts.
In the early twentieth century it seemed that Darwin’s prediction had been borne out. A giant hawk moth from Madagascar, Xanthopan morganii praedicta, was captured, with a proboscis that measured more than nine inches long. Although no one has actually seen the insect feeding on the flower, the discovery is still remarkable, and strongly suggestive of the coevolution of the orchid and moth. Other insects that have relationships with highly specific plants, such as the mega nosed fly and other, related long-nosed fly species of southern Africa, provide even better evidence of the reciprocal links between planes and their pollinators.
Darwin would have been amazed that some flies in southern Africa have longer tongues than most hawk moths do. After all, the flies’ bodies are several times smaller than the hawk moths’ are. Flies are described as long-nosed if their mouthparts are longer than three quarters of an inch. By that criterion, more than a dozen long-nosed fly species are native to southern Africa. They belong to two families. The nemestrinids, or tangle-veined flies (which include the mega-nosed fly), feed solely on nectar, whereas the tabanids, or horseflies, feed mostly on nectar, though female tabanids have separate mouthparts to suck blood for their developing eggs.
Like all other long-nosed flies, the mega nosed fly is the sole pollinator to a group of unrelated plant species such a group is known as a guild. The plant guild of the mega nosed fly includes species from a wide variety of plant families, including geraniums, irises, orchids, and violets.
Even though guild members may be only distantly related, all of them have roughly the same characteristics. For example, plants in the long-nosed fly guild all have long, straight floral tubes or spurs brightly colored flowers that are open during the day and no scent. The defining traits of a guild together form what botanists call a pollination syndrome. For example, bird-pollinated flowers are typically large, red, and unscented, whereas moth-pollinated flowers are more likely to be long, narrow, white, and scented in the evening.
The most important trait in the pollination syndrome of the long-nosed fly (and indeed, in all pollination syndromes of long-nosed insects) is a deep, tubular flower or floral spur. One of us (Johnson) and Kim E. Steiner of the Compton Herbarium in Claremont, South Africa, studied the orchid Disadraconis, a southern African plant with a deep, tubular floral spur. The two investigators artificially shortened the spurs of some orchids in a habitat where the only pollinators present were long-nosed flies. The plants whose spurs remained long got more pollen, and were more likely to produce fruits, than the ones whose spurs were shortened.
Yet short floral spurs are not necessarily a reproductive disadvantage. Shorter spurs would make it possible for a wider range of pollinators to access the nectar, if various potential pollinators are present. Instead, longer spurs only seem to be an advantage when long-tongued insects are the sole pollinators. Johnson and Steiner found that differences in spur length among populations cannot be blamed on differences in moisture or temperature, thus reinforcing their conclusion that spur length was an adaptation to the local distributions of long-tongued flies.
Not only does spur length correlate statistically with pollinator traits, but a direct causal connection can be demonstrated. Johnson and Ronny Alexandersson, a botanist at Uppsala University in Sweden, studied South African Gladiolus flowers pollinated by long-tongued hawk moths. When the hawk moth proboscises were long compared to the length of the flower tube, the hawk moths did not efficiently pick up pollen, and the flowers did not reproduce well. When the hawk moth proboscises were relatively short, pollen was more readily transferred, and the plants were more likely to be fertilized and bear fruit. Thus the length of the pollinator’s proboscis exerts a strong pressure on the reproductive success of the flowers.
Those studies and others suggest that what Darwin predicted of the Malagasy orchid is a rather general phenomenon: hawk moths and long-nosed flies coevolved with their plant partners. As floral tubes became longer, so did the pollinators’ proboscises, and those led, in turn, to even longer flowers. As the lengths of the flower tube and the insect proboscis converge, a remarkable degree of specialization develops. The plants come to rely for pollination on the few insect species that can reach their flowers’ nectar supplies.
There are advantages for the specialists on both sides of this relationship. The long-nosed flies obviously get privileged access to pools of nectar. And the plants pollinated by long-nosed flies benefit from a near-exclusive pollen courier service–or at least one that minimizes the risk of delivery to the wrong address. But specializing can also be a risky strategy for the plants if the pollinators are less interested in fidelity than the plants are. Long-nosed flies could not survive on the nectar they could get by visiting just one plant species the flies must visit several plant species to gather the energy they need. Johnson and Steiner observed mega nosed flies visiting at least four species with deep flowers.
Such promiscuous behavior could be detrimental to the plants. A fly might end up carrying pollen from one species to a different species in the guild, thereby wasting the pollen. Worse, the foreign pollen could end up clogging the stigmata, the female reproductive structures, of the receiving flowers, preventing them from getting the “right” pollen. But the stigmata of plants in the guild of the mega nosed fly do not clog, because among those plants yet another clever adaptation to specialized pollination has evolved. Each plant species arranges its anthers, the male reproductive structures, in a characteristic position. That way, the pollen from each species sticks to the pollinator’s body in a distinct but consistent, plant-specific location. The fly becomes an even more efficient courier, carrying pollen from various plant species simultaneously, say, on its head, legs, and thorax.
The risks of specialization are not confined to the flowers. Just as the flies are unfaithful partners, some flowers are dishonest about signaling a nectar reward. The orchid D. draconis, for instance, is not the mutualistic partner it seems. The flower attracts the mega-nosed fly because it looks like other members of the fly’s guild. But, whereas the fly carries the orchid’s pollen, the orchid offers no nectar in return.
The risk of falling for such a trick seems a small price for the flies to pay for the benefits of specialization. But specialization also carries a much graver risk–in fact the ultimate risk–for both members of the partnership because the disappearance of either partner is likely to doom the other one, as well. Some plant species have mechanisms, such as vegetative reproduction or self-pollination, that may help sustain their populations in the short run. But in the long run, without their pollinators, the species will slowly and irrevocably decline. Pollinating insects may be more flexible in some cases, but are still vulnerable if a key food source disappears.
Unfortunately, in southern Africa that is just what is happening to many plants and their long-nosed fly partners. Often not even closely related insect species can help in pollination. For affected plants, the loss of a single fly species means extinction. And examples of that gloomy cascade have already been observed. Peter Goldblatt of the Missouri Botanical Garden in St. Louis and John C. Manning of the Compton Herbarium have ‘reported that many populations of long-nosed flies are threatened by the loss of their wetland breeding habitat, and also, possibly, by the loss of other insects they parasitize during their larval stages. In some habitats, flowers in the long-nosed fly guild already produce no seeds, because their pollinator is locally extinct.
Naturalists have accepted the concepts of guilds and pollinator syndromes for many years, and predicting which pollinators regularly visit which plants has become something of a cottage industry. But just how common is pollinator specialization in southern Africa? Promiscuity could turn out to be a more successful–and more widespread–strategy than specialization, even among plants that seem to fit into identifiable guilds.
In recent years ecologists have discovered that just because plants and insects appear to form a pollination guild does not guarantee they never venture outside it. For example, ecologists have noted that in years when hummingbird populations are low, flowers ordinarily pollinated by hummingbirds can fill up with nectar and become pollinated effectively by bees. Likewise, bees once thought to specialize in only one or two plant species turn out to forage on a variety of plants.
The take-home lesson has been that the syndrome concept is no substitute for careful field observation. Some investigators even think that the concept has caused botanists to overlook generalists. In the Northern Hemisphere, for instance, studies suggest that generalization is the norm, not the exception. Johnson and Steiner recently completed a study showing that members of the orchid and asclepiad families in the Northern Hemisphere tend to rely on between three and five pollinators each. In contrast, plants from the same families in the Southern Hemisphere rely on just one pollinator each.
So why might generalization be more common in the Northern Hemisphere than it is in the Southern Hemisphere? Perhaps the reason is that social bees, which are largely opportunistic, dominate pollinator faunas in northern regions. In the Southern Hemisphere, by contrast, social bees are mostly absent, replaced instead by more specialized pollinators such as the long-nosed flies and hawk moths.
But that is just a broad generalization itself. More data on the geographic distribution of pollinator specialization needs to be gathered, particularly in tropical countries. The data is vital, not only to advance the specialization debate, but also to protect as many of these unique species and relations as possible, lest they disappear forever.
Catnip repels insects. Scientists may have finally found out how
Catnip (Nepeta cataria) may have a euphoric effect on cats, but the plant deters insects by triggering a chemical sensor for irritants, a new study shows.
Turnip Towers/Alamy Stock Photo
A whiff of catnip can make mosquitoes buzz off, and now researchers know why.
The active component of catnip (Nepeta cataria) repels insects by triggering a chemical receptor that spurs sensations such as pain or itch, researchers report March 4 in Current Biology. The sensor, dubbed TRPA1, is common in animals — from flatworms to people — and responds to environmental irritants such as cold, heat, wasabi and tear gas. When irritants come into contact with TRPA1, the reaction can make people cough or an insect flee.
Catnip’s repellent effect on insects — and its euphoric effect on felines — has been documented for millennia. Studies have shown that catnip may be as effective as the widely used synthetic repellent diethyl-m-toluamide, or DEET (SN: 9/5/01). But it was unknown how the plant repelled insects.
So researchers exposed mosquitoes and fruit flies to catnip and monitored the insects’ behavior. Fruit flies were less likely to lay eggs on the side of a petri dish that was treated with catnip or its active component, nepetalactone. Mosquitoes were also less likely to take blood from a human hand coated with catnip. Insects that had been genetically modified to lack TRPA1, however, had no aversion to the plant. That behavior — coupled with experiments in lab-grown cells that show catnip activates TRPA1 — suggests that insect TRPA1 senses catnip as an irritant.
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Puzzling out how the plant deters insects could help researchers design potent repellents that may be easier to obtain in developing countries hit hard by mosquito-borne diseases. “Oil extracted from the plant or the plant itself could be a great starting point,” says study coauthor Marco Gallio, a neuroscientist at Northwestern University in Evanston, Ill.
If a plant can make a chemical that activates TRPA1 in a variety of animals, none are going to eat it, says Paul Garrity, a neuroscientist at Brandeis University in Waltham, Mass., who was not involved in the work. Catnip probably didn’t evolve in response to predation from ancient mosquitoes or fruit flies, he says, since plants aren’t on the insects’ main menu. Instead, these insects might be collateral damage in catnip’s fight with some other plant-nibbling insect.
Catnip may deter insects like this yellow fever mosquito (Aedes aegypti) by triggering a chemical sensor that, in humans, detects pain or itch. Marcus Stensmyr
The finding “does make you wonder what the target is in cats,” says Craig Montell, a neuroscientist at the University of California, Santa Barbara also not involved with the study. The question is not only whether catnip targets TRPA1 in cats but also whether the plant might send signals through different cells — such as those for pleasure — in the feline nervous system, Montell says.
Luckily, the plant’s bug-off nature doesn’t affect people — a sign of a good repellent, Gallio says. Human TRPA1 did not respond to catnip in lab-grown cells. Plus, he says, “the great advantage is that you can grow [catnip] in your backyard.”
Though maybe don’t plant catnip in the garden, says study coauthor Marcus Stensmyr, a neuroscientist at Lund University in Sweden. A pot might be better, he says, since catnip can spread like a weed, taking over a garden.
Questions or comments on this article? E-mail us at [email protected]
A version of this article appears in the March 27, 2021 issue of Science News.
Francis’ Woolly Horseshoe Bat: New Species of Bat Discovered
The Francis’ woolly horseshoe bat (Rhinolophus francisi). Image credit: Natural History Museum, London.
The new species belongs to the bat genus Rhinolophus, the single extant genus in the family Rhinolophidae.
Members of this genus typically have a horseshoe-shaped, leaf-like structure on their nose, earning them the common name ‘horseshoe bats.’
The bats use this structure to focus the sound of their echolocation calls, which are used for navigation and finding food, according to an international team of scientists, including Dr Roberto Portela Miguez from the Natural History Museum, London, UK.
The name of the newly discovered Rhinolophus species – the Francis’ woolly horseshoe bat (Rhinolophus francisi) – honors Dr Charles M. Francis, a scientist who collected the type specimen of the new species in Malaysia in 1983.
“The new species is currently known from only six records with two records in Sabah, Malaysian Borneo three in Indonesian Borneo (Kalimantan) and a single record in Thailand,” Dr Portela Miguez and his colleagues said.
“The species may be distributed more widely in these regions, but has been rarely captured despite extensive surveys. Genetic data also suggest that this species is likely to occur in Vietnam, although this needs to be confirmed.”
The team also discovered Rhinolophus francisi thailandicus, a subspecies of the Francis’ woolly horseshoe bat, in the jungles of Thailand.
“New species for groups like insects and fishes are discovered fairly regularly, but new mammals are rarer,” Dr Portela Miguez said.
“This is a reminder of how much we still have to discover about the natural world.”
Research describing the Francis’ woolly horseshoe bat and its subspecies is published online in the journal Acta Chiropterologica.
Pipat Soisook et al. 2015. Description of a New Species of the Rhinolophus trifoliatus-Group (Chiroptera: Rhinolophidae) from Southeast Asia. Acta Chiropterologica 17 (1): 21-36 doi: 10.3161/15081109ACC2015.17.1.002